Question: $A$ $B$ $C$ If: $ BC = 9x + 8$, $ AB = 9x + 8$, and $ AC = 88$, Find $BC$.
Solution: From the diagram, we can see that the total length of ${AC}$ is the sum of ${AB}$ and ${BC}$ $ {AB} + {BC} = {AC}$ Substitute in the expressions that were given for each length: $ {9x + 8} + {9x + 8} = {88}$ Combine like terms: $ 18x + 16 = {88}$ Subtract $16$ from both sides: $ 18x = 72$ Divide both sides by $18$ to find $x$ $ x = 4$ Substitute $4$ for $x$ in the expression that was given for $BC$ $ BC = 9({4}) + 8$ Simplify: $ {BC = 36 + 8}$ Simplify to find ${BC}$ : $ {BC = 44}$